6.1 Catch error

In 6.1, the unittests will not give the message "At least one test failed when loading the modules."
Look for "ERROR openerp_test", which will apear in both 6.1 and 7.0.

[Example case with false positive](https://travis-ci.org/OCA/product-attribute/builds/29492172)
Merge pull request #24 from bwrsandman/patch-2

Catch error to avoid false positives